Display with organic light emitting elements including a light emitting layer provided by transferring a transfer layer from a donor substrate to an acceptor substrate

ABSTRACT

A display is provided. The display includes an acceptor substrate including red light-emitting elements arranged in a first column, green light-emitting elements arranged in a second column, and blue light-emitting elements arranged in a third column. The light-emitting elements are arranged along a row direction and are each obtained by arranging rectangular organic light-emitting elements for generating light of one of red, green, and blue along a longitudinal direction of the organic light-emitting elements.

CROSS REFERENCES TO RELATED APPLICATIONS

The present application claims priority related to Japanese PatentApplication JP 2007-064787 filed in the Japan Patent Office on Mar. 14,2007, the entire contents of which being incorporated herein byreference.

BACKGROUND

The present application relates to a display that employs organiclight-emitting elements having a transferred light-emitting layerobtained by a thermal transfer method.

As one of manufacturing methods for an organic light-emitting element, apattern fabrication method employing thermal transfer has beendisclosed. In the thermal transfer method, a donor component arisingfrom formation of a transfer layer containing a light-emitting materialover a support is formed. Subsequently, this donor component is disposedto face an acceptor substrate for forming an organic light-emittingelement, and the transfer layer is transferred to the acceptor substrateby irradiation with a radiant ray under a low-pressure environment. Asthe support, a rigid material such as glass is used in some cases (referto e.g. Japanese Patent Laid-Open No. 2006-309994 (Patent document 1)),and a flexible film is used in other cases (refer to e.g. JapanesePatent Laid-Open No. 2003-168569 (Patent document 2)). In the lattercases, the transfer is carried out in such a was that the donorcomponent is brought into complete contact with an electrode over theacceptor substrate. In the former cases, an insulating layer fordefining a light-emmission area is provided over the acceptor substrate.Subsequently, the irradiation with a radiant ray is performed in thestate in which the donor substrate is separated from the acceptorsubstrate by the distance equivalent to the height of this insulatinglayer, to thereby sublime or evaporate the transfer layer, so that thetransfer layer is transferred to the acceptor substrate.

However, as described in Patent document 1, if a rigid material such asglass is used as the support or the donor component, there is room forimprovement in the size and shape of the insulating layer for definingthe light-emission area and the width and position of the transferpattern, for suppression of the distribution of the film thickness ofthe transferred light-emitting layer in the light-emission area andcolor mixing into an adjacent light-emission area.

In Japanese Patent Laid-Open No. 2003-168569, countermeasures against afringe pattern in a transfer method of subliming or evaporating atransfer layer are disclosed. However, fundamental measures to suppressthe distribution of the film thickness of the transferred light-emittinglayer in the light-emission area and to prevent color mixing are notdescribed in this document.

Furthermore, there is a fear that so-called reverse transfer occurs inthe transfer step as shown in FIG. 30A. Specifically, in the transferstep, a donor substrate 840 on which a transfer layer 850 is formed isbrought into tight contact with, by using pressure difference from theatmospheric pressure, an acceptor substrate 811 over which a firstelectrode 813, an insulating layer 814, and a hole injection layer andhole transport latter 815AB are formed. Therefore, the tight-contactpressure by the donor substrate 840 possibly causes pressure-transfer ofthe already-deposited hole injection layer and hole transport layer815AB. Such a reverse transfer phenomenon readily occurs when heating bylaser light at the time of the transfer is added to the pressuring bythe donor substrate 840. If the reverse transfer occurs, the depositedsurface of the hole injection layer and hole transport layer 815AB overthe acceptor substrate 811 is disturbed, and thus current leakage CLthrough the defect resulting from the reverse transfer will occur asshown in FIG. 30B. This current leakage CL problematically causes streakunevenness and mottled unevenness at the time of the lighting of thedisplay. For this reason, assured suppression of the reverse transfer isdesired.

SUMMARY

The present application in an embodiment provides a display that hassuppressed distribution of the film thickness of a transferredlight-emitting layer in a light-emission area and enhanced displayquality.

According to an embodiment, there is provided a display including anacceptor substrate configured to have thereon a red light-emittingelement column, a green light-emitting element column, and a bluelight-emitting element column that are arranged along the row directionand are each obtained by arranging rectangular organic light-emittingelements for generating light of one of red, green, and blue along thelongitudinal direction of the organic light-emitting elements. Theorganic light-emitting element includes a first electrode, an insulatinglayer having an aperture corresponding to a light-emission area of thefirst electrode, an organic layer that includes a light-emitting layerand is formed at least on the light-emission area, and a secondelectrode. The light-emitting layer in at least the red light-emittingelement column and the green light-emitting element column is atransferred light-emitting layer formed by disposing the acceptorsubstrate over which the first electrode and the insulating layer areformed and a donor substrate over which a transfer layer containing alight-emitting material is formed in such a way that the acceptorsubstrate and the donor substrate face each other with the intermediaryof the insulating layer therebetween, and carrying out irradiation witha radiant ray to sublime or evaporate the transfer layer to therebytransfer the transfer layer at least onto the light-emission area. Ifthe intersection of the tangent to the insulating layer drawn from anend of the light-emission area with the surface of the donor substrateis A and the intersection of the perpendicular line to the acceptorsubstrate drawn down from the A with the surface of the insulating layeris C, the transferred light-emitting layer includes the C. The term“tangent” refers to the tangent to the insulating layer drawn from anend of the light-emission area as described above if the side surface ofthe insulating layer is an inclined surface or a convex surface. Incontrast, if the side surface of the insulating layer is a concavesurface, the “tangent” refers to the straight line connecting an end ofthe light-emission area with a position on the side surface of theinsulating layer protruding toward the light-emission area such that theresulting tangent straight line has the highest possible angle ofinclination relative to the surface of the acceptor substrate.

In the display according an embodiment, under the definition that theintersection of the tangent to the insulating layer drawn from the endof the light-emission area with the surface of the donor substrate is Aand the intersection of the perpendicular line to the acceptor substratedrawn down from A with the surface of the insulating layer is C, thetransferred light-emitting later includes C. This feature providesnarrowed distribution of the film thickness of the transferredlight-emitting layer in the light-emission area. Thus, luminanceunevenness, color unevenness, the lowering of the light-emissionefficiency, and so on are suppressed, which enhances the displayquality.

Additional features and advantages are described herein, and will beapparent from the following Detailed Description and the figures.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a diagram showing the configuration of a display according toa first embodiment:

FIG. 2 is a diagram showing one example of a pixel drive circuit shownin FIG. 1;

FIG. 3 is a plan view showing the configuration of a displays area shownin FIG. 1;

FIG. 4 is a sectional view showing the configuration of organiclight-emitting elements shown in FIG. 3;

FIG. 5 is a sectional view showing an intermediate step in a method formanufacturing the display shown in FIG. 1, and showing the positionalrelationship between an acceptor substrate and a donor substrate;

FIG. 6 is a sectional view showing a step subsequent to the step of FIG.5, and showing the positional relationship among a light-emitting layerof an organic light-emitting element, a light-emission area of a firstelectrode, and an insulating layer;

FIG. 7 is a plan view showing the light-emitting layer formed in thestep shown in FIG. 6;

FIG. 8 is a sectional view showing a modification example of theinsulating layer shown in FIG. 5;

FIG. 9 is a sectional view showing another modification example of theinsulating layer shown in FIG. 5;

FIG. 10 is a sectional view showing yet another modification example ofthe insulating layer shown in FIG. 5;

FIG. 11 is a sectional view showing yet another modification example ofthe insulating layer shown in FIG. 5;

FIGS. 12A and 12B are sectional views showing yet another modificationexample of the insulating layer shown in FIG. 5;

FIGS. 13A and 13B are sectional views showing yet another modificationexample of the insulating layer shown in FIG. 5;

FIGS. 14A and 14B are sectional views showing yet another modificationexample of the insulating layer shown in FIG. 5;

FIG. 15 is a sectional view showing yet another modification example ofthe insulating layer shown in FIG. 5;

FIG. 16 is a sectional view showing yet another modification example ofthe insulating layer shown in FIG. 5;

FIG. 17 is a sectional view showing yet another modification example ofthe insulating layer shown in FIG. 5;

FIGS. 18A and 18B are sectional views showing the shape of an insulatinglayer in a display according to a second embodiment;

FIGS. 19A and 19B are sectional views showing a modification example ofthe insulating layer shown in FIGS. 18A and 18B;

FIGS. 20A and 20B are sectional views showing another modificationexample of the insulating layer shown in FIGS. 18A and 18B;

FIGS. 21A and 21B are sectional views showing yet another modificationexample of the insulating layer shown in FIGS. 18A and 18B;

FIG. 22 is a diagram showing results relating to Working example 1;

FIG. 23 is a diagram showing results relating to Working example 2;

FIG. 24 is a plan view showing the schematic configuration of a moduleincluding the display according to an embodiment;

FIG. 25 is a perspective view showing the appearance of Applicationexample 1 of the display according to an embodiment;

FIGS. 26A and 26B are perspective views showing the appearance of thefront side and rear side, respectively, of Application example 2 of thedisplay;

FIG. 27 is a perspective view showing the appearance of Applicationexample 3 of the display;

FIG. 28 is a perspective view showing the appearance of Applicationexample 4 of the display;

FIGS. 29A to 29G are diagrams showing Application example 5 of thedisplays A and B are a front view and side view, respectively, of theopened state, and C, D, E, F, and G are a front view, left-side view,right-side view, top view, and bottom view, respectively, of the closedstate; and

FIGS. 30A and 30B are diagrams for explaining problems of a related-arttransfer method.

DETAILED DESCRIPTION

Embodiments of the present application will be described in detail belowwith reference to the accompanying drawings

(First Embodiment)

FIG. 1 shows the configuration of a display according to a firstembodiment of the present invention. This display is used as anextremely-thin organic light-emitting color display or the like. Forexample, for this display, a display area 110 in which plural organiclight-emitting elements 10R, 10G, and 10B, which will be describedlater, are arranged in a matrix is formed on an acceptor substrate 11composed or glass. Furthermore, around this display area 110, a signalline drive circuit 120 and a scan line drive circuit 130 are formed asdrivers for video displaying.

Pixel drive circuits 140 are formed in the display area 110. FIG. 2shows one example of the pixel drive circuit 140. This pixel drivecircuit 140 is formed below a first electrode 13, which will bedescribed later, and is an active-type drive circuit that includes adrive transistor Tr1, a write transistor Tr2, a capacitor (holdingcapacitor) Cs between these transistors, and an organic light-emittingelement 10R (or 10G, 10B) connected in series to the drive transistorTr1 between a first power supply line (Vcc) and a second power supplyline (GND). The drive transistor Tr1 and the write transistor Tr2 areformed of a general thin film transistor (TFT). The structures of thesetransistors are not particularly limited: these transistors may haveeither a reverse-stagger structure (so-called bottom-gate structure) ora stagger structure (top-gate structure) for example.

For the pixel drive circuits 140, plural signal lines 120A are disposedalong the column direction and plural scan lines 130A are disposed alongthe row direction. Each of the intersections of the signal lines 120Awith the scan lines 130A corresponds to an), one of the organiclight-emitting elements 10R, 10G, and 10B (sub-pixel). Each signal line120A is connected to the signal line drive circuit 120. From this signalline drive circuit 120, image signals are supplied to the sourceelectrodes of the write transistors Tr2 via the signal lines 120A. Eachscan line 130A is connected to the scan line drive circuit 130. Fromthis scan line drive circuit 130, scan signals are sequentially suppliedto the gate electrodes of the write transistors Tr2 via the scan lines130A.

FIG. 3 shows one example of the planar configuration of the display area110. In the display area 110, the organic light-emitting elements 10Rfor generating red light, the organic light-emitting elements 10G forgenerating green light, and the organic light-emitting elements 10B forgenerating blue light are in turn formed into a matrix as a whole. Theorganic light-emitting elements 10R, 10G, and 10B each have arectangular planar shape, and form red light-emitting element columns110R, green light-emitting element columns 110G, and blue light-emittingelement columns 110B arising from arrangement of the elements along thelongitudinal direction of the elements (column direction). These redlight-emitting element columns 110R, green light-emitting elementcolumns 110G, and blue light-emitting element columns 110B are arrangedalong the row direction in the display area 110. The combination of theadjacent organic light-emitting elements 10R, 10G, and 10B serves as onepixel 10. The pixel pitch is e.g. 300 μm.

FIG. 4 shows the sectional configuration of the organic light-emittingelements 10R, 10G, and 10B shown in FIG. 3. Each of the organiclight-emitting elements 10R, 10G, and 10B has a configuration obtainedby stacking the first electrode 13 as the anode, an insulating layer 14,an organic layer 15 including a light-emitting layer 15C to be describedlater, and a second electrode 16 as the cathode in that order from thesubstrate side with the intermediary of the drive transistor in theabove-described pixel drive circuit 140 (not shown) and a planarizationinsulating film (not shown).

The organic light-emitting elements 10R, 10G, and 10B are covered by aprotective film 17 composed of a silicon nitride (SiNx). Furthermore, asealing substrate 30 composed of glass or the like is bonded across theentire surface over this protective film 17 with the intermediary of anadhesive layer 20, so that the organic light-emitting elements 10R, 10G,and 10B are sealed.

The first electrode 13 is composed of e.g. ITO (indium-tin compositeoxide).

The insulating layer 14 is to assure insulation between the firstelectrodes 13 and the second electrode 16 and allow the light-emissionareas to have a desired shape accurately. The insulating layer 14 iscomposed of e.g. photosensitive resin such as polyimide. In theinsulating layer 14, apertures are provided corresponding tolight-emission areas 13A of the first electrodes 13. The organic layer15 and the second electrode 16 may be provided not only over thelight-emission areas 13A but also over the insulating layer 14continuously. However, light emission occurs only in the apertures ofthe insulating layer 14.

The organic layer 15 has a configuration obtained by stacking a holeinjection layer and hole transport layer 15AB, the light-emitting layer15C, and an electron transport layer and electron injection layer 15DEin that order from the first electrode side. However, the provision ofthe layers other than the light-emitting layer 15C is according to need.The organic layer 15 may have different configurations depending on thecolors of light emitted by the organic light-emitting elements 10R, 10G,and 10B. The hole injection layer is to enhance the hole injectionefficiency, and is a buffer layer for preventing leakage. The holetransport layer is to enhance the efficiency of hole transportation tothe light-emitting layer 15C. In the light-emitting layer 15C, therecombination between electrons and holes occurs and thus light isgenerated in response to electric field application. The electrontransport layer is to enhance the efficiency of electron transportationto the light-emitting layer 15C. The electron injection layer has athickness of e.g. about 0.3 nm and is composed of LiF, Li₂O, or thelike. In FIG. 4, the hole injection layer and the hole transport layerare represented as one layer (the hole injection layer and holetransport layer 15AB), and the electron transport layer and the electroninjection layer are represented as one layer (the electron transportlayer and electron injection layer 15DE).

The hole injection layer of the organic light-emitting element 10R has athickness in the range of 5 nm to 300 nm, and is composed of4,4′,4″-tris(3-methylphenylphenylamino)triphenylamine (m-MTDATA) or4,4′,4″-tris(2-naphthylphenylamino)triphenylamine (2-TNATA), forexample. The hole transport layer of the organic light-emitting element10R has a thickness in the range of 5 nm to 300 nm, and is composed ofbis[(N-naphthyl)-N-phenyl]benzidine (α-NPD), for example. Thelight-emitting layer 15C of the organic light-emitting element 10R has athickness in the range of 10 nm to 100 nm, and is composed of9,10-di-(2-naphthyl)anthracene (ADN) doped with 30-wt. %2,6≡bis[(4′≡methoxydiphenylamino)styryl]≡1,5≡dicyanoniaphthalene (BSN),for example. The electron transport layer of the organic light-emittingelement 10R has a thickness in the range of 5 nm to 300 nm, and iscomposed of 8≡hydroxyquinoline aluminum (Alq₃), for example.

The hole injection layer of the organic light-emitting, element 10G hasa thickness in the range of 5 nm to 300 nm, and is composed of m-MTDATAor 2-TNATA, for example. The hole transport layer of the organiclight-emitting element 10G has a thickness in the range of 5 nm to 300nm, and is composed of α-NPD, for example. The light-emitting layer 15Cof the organic light-emitting element 10G has a thickness in the rangeof 10 nm to 100 nm, and is composed of ADN doped with 5-wt. % coumarin6, for example. The electron transport layer of the organiclight-emitting element 10G has a thickness in the range of 5 nm to 300nm, and is composed of Alq₃, for example.

The hole injection layer of the organic light-emitting element 10B has athickness in the range of 5 nm to 300 nm, and is composed of m-MTDATA or2-TNATA, for example. The hole transport layer of the organiclight-emitting element 10B has a thickness in the range of 5 nm to 300nm, and is composed of α-NPD, for example. The light-emitting layer 15Cof the organic light-emitting element 10B has a thickness in the rangeof 10 nm to 100 nm, and is composed of ADN doped with 2,5-wt %4,4′≡bis[2≡{(4≡(N,N≡diphenylamino)phenyl)}vinyl]biphenyl (DPAVBi), forexample. The electron transport layer of the organic light-emittingelement 10B has a thickness in the range of 5 nm to 300 nm, and iscomposed of Alq₃, for example.

FIGS. 5 and 6 show the positional relationship among the light-emittinglayer 15C of the organic light-emitting elements 10R, 10G, and 10B, thelight-emission area 13A of the first electrode 13, and the insulatinglayer 14. As described later, the light-emitting layer 15C of theorganic light-emitting elements 10R, 10G, and 10B is a transferredlight-emitting layer formed as follows. Specifically, the acceptorsubstrate 11 over which the first electrodes 13 and the insulating layer14 have been formed and a donor substrate 40 on which a transfer layer50 containing a light-emitting material has been formed are disposed toface each other with the intermediary of the insulating layer 14therebetween. In this state, irradiation with laser light is carried outto sublime or evaporate the transfer layer 50, to thereby transfer thetransfer later 50 at least onto the light-emission area 13A.Furthermore, under the definition that the intersection of the tangentto the insulating layer 14 drawn from an end of the light-emission area13A with the surface of the donor substrate 40 is A and the intersectionof the perpendicular line to the acceptor substrate 11 drawn down from Awith the surface of the insulating layer 14 is C, the light-emittinglayer 15C is so formed as to include C.

The second electrode 16 shown in FIG. 4 has a thickness in the range of5 nm to 50 nm, and is composed of an elemental metal such as aluminum(Al), magnesium (Mg), calcium (Ca), or sodium (Na), or an alloy of an)of these metals, for example. Among them, an alloy of magnesium andsilver (MgAg alloy) and an alloy of aluminum (Al) and lithium (Li) (AlLialloy) are preferable.

The protective film 17 shown in FIG. 4 is to prevent water and so onfrom entering the organic layer 15. It is composed of a material withlow water permeability and low water absorption and has sufficientthickness. Furthermore, the protective film 17 has high transmittancefor light generated by the light-emitting layer 15C: it is composed of amaterial having a transmittance of 80% or higher for example. Such aprotective film 17 has a thickness in the range of about 2 μm to 3 μm,and is composed of an inorganic amorphous insulating material forexample. Specifically, amorphous silicon (α-Si), amorphous siliconcarbide (α-SiC), amorphous silicon nitride (α-Si_(1-X)N_(X)), andamorphous carbon (α-C) are preferable. These inorganic amorphousinsulating materials include no grain and thus have low waterpermeability, and hence will serve as a favorable protective film 17.Alternatively, the protective film 17 may be composed of a transparentconductive material such as ITO.

The adhesive layer 20 shown in FIG. 4 is composed of e.g. heat-curableresin or UV-curable resin.

The sealing substrate 30 shown in FIG. 4 is located on the secondelectrode side of the organic light-emitting elements 10R, 10G, and 10B.It is to seal the organic light-emitting elements 10R, 10G, and 10Btogether with the adhesive layer 20, and is composed or a material, suchas glass, having transparency for light generated by the organiclight-emitting elements 10R, 10G, and 10B. The sealing substrate 30 maybe provided with e.g. a color filter (not shown) so that light generatedby the organic light-emitting elements 10R, 10G, and 10B may beextracted through the color filter and external light reflected by theorganic light-emitting elements 10R, 10G, and 10B and interconnectsamong these elements may be absorbed by the color filter to thereby,improve the contrast.

Although the color filter may be provided on either surface of thesealing substrate 30, it is preferable that the color filter be providedon the surface closer to the organic light-emitting elements 10R, 10G,and 10B. This is because the color filter is not exposed to the outsidebut can be protected by the adhesive layer 20. In addition, this isbecause the distance between the light-emitting layer 15C and the colorfilter is small and thus the occurrence of color mixing due to theentering of light emitted from the light-emitting layer 15C into thecolor filter of another color can be avoided. The color filter includesa red filter, green filter, and blue filter (none of them are shown inthe drawing), and these filters are in turn disposed corresponding tothe organic light-emitting elements 10R, 10G and 10B.

The red, green, and blue filters are each formed into e.g. a rectangularshape without leaving a gap among the filters. Each of the red, green,and blue filters is composed of resin mixed with a pigment. Throughselection of the pigment, the optical transmittance of the filter is soadjusted that the optical transmittance for the wavelength range of theintended red, green, or blue is high and the optical transmittance forthe other wavelength range is low.

This display can be manufactured in the following manner for example.

Initially, the acceptor substrate 11 composed of the above-describedmaterial is prepared, and the pixel drive circuits 140 each includingthe drive transistor are formed on this acceptor substrate 11.Subsequently, the planarization insulating film is formed throughapplying of photosensitive resin across the entire surface, and thenexposure and development are carried out to thereby pattern the filminto a predetermined shape and form connection holes (not shown) forconnection between the drive transistor and the first electrode 13,followed by baking.

Subsequently, the first electrodes 13 composed of the above-describedmaterial are formed by e.g. sputtering, and then are processed into apredetermined shape by e.g. dr etching. At a predetermined position onthe acceptor substrate 11 an alignment mark used for alignment with adonor substrate in a transfer step to be described later is formed.

Subsequently, photosensitive resin is applied across the entire surfaceof the acceptor substrate 11, and then apertures are providedcorresponding to the light-emission areas by e.g. photolithography,followed by baking. As a result, the insulating layer 14 is formed.

Thereafter, by e.g. evaporation, the hole injection layer and holetransport layer 15AB having the above-described thickness and iscomposed or the above-described material are sequentially deposited.

After the formation of the hole injection layer and hole transport layer15AB, the light-emitting layer 15C is formed by a thermal transfermethod. Specifically, as shown in FIG. 5, the acceptor substrate 11 overwhich the first electrodes 13 and the insulating layer 14 have beenformed and the donor substrate 40 on which the transfer layer 50containing a light-emitting material has been formed are disposed toface each other with the intermediary of the insulating layer 14therebetween, and both the substrates are brought into tight contactwith each other under a vacuum environment. Thereafter, the substratesare brought out to an atmospheric-pressure environment in such a waythat the vacuum between both the surfaces is kept by using a vacuumholding frame. Thus, due to the pressure difference between the insideand outside of the substrates, the donor substrate 40 is brought intotight contact with the acceptor substrate 11 uniformly. However, thedistance equivalent to the thickness (height) of the insulating layer 14is kept between the surface of the transfer layer 50 on the donorsubstrate 40 and the surface of the hole injection layer and holetransport layer 15AB (not shown in FIG. 6) over the acceptor substrate11.

Subsequently, irradiation with laser light is carried out to sublime orevaporate the transfer layer 50 to thereby transfer the transfer layer50 at least onto the light-emission area 13A. Thereby, thelight-emitting layer 15C is formed as shown in FIGS. 6 and 7. At thistime, under the definition that the intersection of the tangent to theinsulating layer 14 drawn from an end of the light-emission area 13Awith the surface of the donor substrate 40 is A and the intersection ofthe perpendicular line to the acceptor substrate 11 drawn down from Awith the surface of the insulating latter 14 is C, the light-emittinglayer 15C is so formed as to include C. This feature allows this displayto have suppressed distribution of the film thickness of thelight-emitting layer 15C in the light-emission area 13A and enhanceddisplay quality.

Furthermore, under the definition that the intersection of the tangentto the insulating layer 14 drawn from an end of the next light-emissionarea 13A adjacent to the light-emission area 13A along the row directionwith the surface of the donor substrate 40 is B and the intersection ofthe perpendicular line to the acceptor substrate 11 drawn down from Bwith the surface of the insulating layer 14 is D, it is preferable thatthe light-emitting layer 15C be so formed as not to include D. This isbecause such a formation way can suppress color mixing into the adjacentlight-emission area 13A and thus can enhance the display quality.

Moreover, under the definition that the distance between theintersections C obtained on both the sides of the light-emission area13A along the row direction is CC and the distance between theintersections D is DD, it is preferable that the width W of thelight-emitting layer 15C along the row direction be set equal to orlarger than CC and smaller than DD. This is because such a formation waycan suppress the distribution of the film thickness of thelight-emitting layer 15C in the light-emission area 13A and color mixinginto the adjacent light-emission area 13A, and thus can enhance thedisplay quality. In addition, the transfer condition such as the spotsize of the laser light can be easily optimized, and thus the timenecessary to determine the condition can be shortened. Moreover, thepositional accuracy margin of the transfer can be predicted, and thus itis also possible to design a shape of the insulating layer 14 forenlarging the margin like modification examples to be described later.

As another feature, it is preferable that the distance d along the rowdirection between the end of the light-emission area 13A and the contactface between the insulating layer 14 and the donor substrate 40 (flatpart of the top surface of the insulating layer 14) be set equal to orlonger than 4 μm. This is because such a feature can suppress adverseeffects such as streak unevenness and mottled unevenness attributed toreverse transfer.

The donor substrate 40 is obtained by forming a photothermal conversionlayer (not shown) on a common substrate (not shown) for example.According to need, an absorbing layer composed of amorphous silicon orthe like may be provided between the common substrate and thephotothermal conversion layer in order to enhance the absorptionefficiency for the laser light, and the photothermal conversion layermay be covered by a protective layer composed of silicon nitride (SiNx)or the like in order to prevent oxidation of the photothermal conversionlayer. The common substrate is composed of a material such as glass,having sufficient robustness to allow alignment with the acceptorsubstrate 11 and high transparency for the laser light. The photothermalconversion layer is composed of a metal material with high absorptivitysuch as molybdenum (Mo), titanium (Ti), chromium (Cr), or an alloycontaining any of these metals. The transfer layer 50 contains thematerial of the light-emitting layer 15C of the above-described organiclight-emitting elements 10R, 10G, and 10B, and is formed by e.g. vacuumevaporation on the donor substrate 40 prepared.

After the formation of the light-emitting layer 15C of the organiclight-emitting elements 10R, 10G, and 10B, the electron transport layerand electron injection layer 15DE and the second electrode 16 are formedby e.g. evaporation. In this manner, the organic light-emitting elements10R, 10G, and 10B are formed.

After the formation of the organic light-emitting elements 10R, 10G, and10B, the protective film 17 composed of the above-described material isformed on these elements. As the method for forming the protective film17, a deposition method in which the energy of deposition particles isso low that no influence is given to the underlying layers, such asevaporation or CVD, is preferable. Furthermore, it is desirable that theformation of the protective film 17 be performed continuously to theformation of the second electrode 16 without the exposure of the secondelectrode 16 to the atmosphere. This is because such a formation way cansuppress the deterioration of the organic layer 15 due to water andoxygen in the atmosphere. Moreover, in this film deposition of theprotective film 17, it is desirable that the deposition temperature beset to a room temperature in order to prevent luminance lowering due tothe deterioration of the organic layer 15 and the deposition conditionbe so set that the film stress is minimized in order to preventseparation of the protective film 17.

Furthermore, for example, the material of the red filter is applied byspin-coating or the like on the sealing substrate 30 composed of theabove-described material, and then is patterned by a photolithographytechnique and baked, to thereby form the red filter. Subsequently, theblue filter and the green filter are sequentially formed similarly tothe red filter.

Thereafter, the adhesive layer 20 is formed on the protective film 17,and the sealing substrate 30 is bonded to the protective film 17 withthe intermediary of the adhesive layer 20. In this bonding, it ispreferable that the surface of the sealing substrate 30 on which thecolor filter has been formed be disposed to face the organiclight-emitting elements 10R, 10G, and 10B. This bonding completes thedisplay shown in FIG. 1.

In the thus obtained display, scan signals are supplied from the scanline drive circuit 130 to the respective pixels via the gate electrodesof the write transistors Tr2, and image signals are held in the holdingcapacitors Cs from the signal line drive circuit 120 via the writetransistors Tr2. Specifically, the drive transistors Tr1 operatedepending on the signals held in the holding capacitors Cs. This appliesdrive currents Id to the respective organic light-emitting elements 10R,10G, and 10B to thereby cause the recombination between holes andelectrons, which results in light emission. This light is extractedthrough the second electrode 16, the color filter, and the sealingsubstrate 30.

In this display, under the definition that the intersection of thetangent to the insulating layer 14 drawn from an end of thelight-emission area 13A with the surface of the donor substrate 40 is Aand the intersection of the perpendicular line to the acceptor substrate11 drawn dozen from A with the surface of the insulating layer 14 is,the light-emitting layer 15C is so formed as to include C. Therefore,the distribution of the film thickness of the light-emitting layer 15Cin the light-emission area 13A is suppressed. Thus, luminanceunevenness, color unevenness, and the lowering of the light-emissionefficiency are suppressed, which enhances the display quality.

As described above, the present embodiment can achieve suppresseddistribution of the film thickness of the light-emitting layer 15C inthe light-emission area 13A and enhanced display quality, because thelight-emitting layer 15C is so formed as to include C under thedefinition that the intersection of the tangent to the insulating layer14 drawn from an end of the light-emission area 13A with the surface ofthe donor substrate 40 is A and the intersection of the perpendicularline to the acceptor substrate 11 drawn down from A with the surface ofthe insulating layer 14 is C.

Furthermore, the light-emitting layer 15C is so formed as not to includeD, under the definition that the intersection of the tangent to theinsulating layer 14 drawn from in end of the next light-emission area13A adjacent to the light-emission area 13A along the row direction withthe surface of the donor substrate 40 is B and the intersection of theperpendicular line to the acceptor substrate 11 drawn down from B withthe surface of the insulating layer 14 is D. Therefore, color mixinginto the adjacent light-emission area 13A can be suppressed, and thusthe display quality, can be enhanced.

Moreover, under the definition that the distance between theintersections C obtained on both the sides of the light-emission area13A along the row direction is CC and the distance between theintersections D is DD, the width W of the light-emitting layer 15C alongthe row direction is set equal to or larger than CC and smaller than DD.This feature can suppress the distribution of the film thickness of thelight-emitting layer 15C in the light-emission area 13A and color mixinginto the adjacent light-emission area 13A, and thus can enhance thedisplay quality. In addition, the transfer condition can be easilyoptimized, and thus the time necessary to determine the condition can beshortened. Moreover, the positional accuracy margin of the transfer canbe predicted, and thus a shape of the insulating layer 14 for enlargingthe margin can be designed like modification examples to be describedlater. This feature can further enhance the yield.

In addition, the distance d along the row direction between the end ofthe light-emission area 13A and the contact face between the insulatinglayer 14 and the donor substrate 40 is set equal to or longer than 4 μm.This feature can suppress adverse effects such as streak unevenness andmottled unevenness attributed to reverse transfer.

In the above-described embodiment, the side surface of the insulatinglayer 14 is an inclined surface. However, the side surface of theinsulating layer 14 may have a convex shape like that shown in FIG. 8 ora concave shape like that shown in FIG. 9. That is, variousmodifications are available.

For example, as shown in FIGS. 10 and 11, a rib (protruding rim orprojection) 14A may be provided on the top surface of the insulatinglayer 14. The rib 14A may extend along both the longitudinal directionand the width direction of the light-emission areas 13A as shown inFIGS. 12A and 12B. Alternatively, it may extend only along thelongitudinal direction of the light-emission areas 13A as shown in FIGS.13A and 13B. More alternatively, it may be provided in a dotted manneras shown in FIGS. 14A and 14B. The rib 14A can be formed by carrying outdouble exposure in the photolithography step for processing theinsulating layer 14.

Furthermore, as shown in FIG. 15, the rib 14A may be provided at boththe ends of the top surface of each portion of the insulating layer 14.Alternatively, as shown in FIGS. 16 and 17, the shapes of the insulatinglayer 14 on both the sides of the light-emission area 13A may bedifferent from each other.

(Second Embodiment)

FIGS. 18A and 18B show the shape of the insulating layer 14 in adisplays according, to a second embodiment of the present invention. Inthis display, only the light-emitting layer 15C of the organiclight-emitting elements 10R and 10G is a transferred light-emittinglayer formed by transfer, whereas the light-emitting layer 15C of theorganic light-emitting elements 10B is formed by a method other thantransfer, such as evaporation. Moreover, if the insulating layer 14 isequally allocated to each of the red, green, and blue light-emittingelement columns 110R, 110G, and 110B, the area of the contact facebetween the insulating layer 14 and the donor substrate 40 in the bluelight-emitting element columns 10B (i.e. the area of the top surface ofthe rib 14A) is the largest. Due to this feature, reverse transferitself can be suppressed in this display. Thus, the occurrence of streakunevenness and mottled unevenness can be avoided, which allowsenhancement in the display quality. Furthermore, the positional accuracymargin of the transfer can be further enlarged, and hence the yield canalso be further enhanced.

In the step for forming the light-emitting layer 15C of the organiclight-emitting elements 10R and 10G, which is a transferredlight-emitting layer, it is preferable to carry out irradiation withlaser light except for the contact face between the insulating layer 14and the donor substrate 40 (the top surface of the rib 14A) to therebyform the light-emitting layer 15C of the organic light-emitting elements10R and 10G onto the area other than this contact face. This is becausesuch a formation way can transfer the light-emitting, layer 15C of theorganic light-emitting elements 10R and 10G with almost no reversetransfer caused, and thus allows reduction in the current leakage amountand suppression of the occurrence of display unevenness.

The rib 14A may extend only along the longitudinal direction of thelight-emission areas 13A as shown in FIGS. 18A and 18B. Alternatively,it may extend along both the longitudinal direction and the widthdirection of the light-emission areas 13A as shown in FIGS. 19A and 19B.More alternatively, it may extend only along the width direction of thelight-emission areas 13A as shown in FIGS. 20A and 20B. Furtheralternatively, it may be provided in a dotted manner as shown in FIGS.21A and 21B.

WORKING EXAMPLES

Specific working examples of the present invention will be describedbelow.

Working Example 1

Similarly to the first embodiment, a display including the red and blueorganic light-emitting elements 10R and 10B was fabricated. In thisfabrication, the width of the light-emission area 13A and the distancesCC and DD were measured. As a result, the width of the light-emissionarea 13A was 70 μm, and the distances CC and DD were 78 μm and 122 μm,respectively. The light-emitting latter 15C was formed bad transfer foreach of the organic light-emitting elements 10R and 10B. The length ofthe longitudinal axis of the beam spot of laser light was varied tovarious values in the range of 70 μm to 130 μm, so that the width W ofthe light-emitting layer 15C along the row direction was varied tovarious values in the range of 70 μm to 130 μm. The shorter axis of thebeam spot of the laser light was fixed to 20 μm, and the laser light wasmoved for scanning in the direction perpendicular to the longitudinaldirection of the beam spot of the laser light. The wavelength and energydensity of the laser light were set to 800 nm and 2.6 E⁻³ J/μm²respectively. The light-emitting layer 15C obtained by the transfer wassubstantially concentric with the light-emission area 13A.

Working Example 2

A display was fabricated in the same manner as that of Working example1, except that the rib 14A shown in FIG. 10 was formed on the topsurface of the insulating layer 14 and the distances CC and DD were setto 82 μm and 118 μm, respectively.

Regarding the displays obtained as Working examples 1 and 2, thedistribution of the Film thickness of the light-emitting layer 15C inthe light-emission area 13A of the organic light-emitting element 10Rand the light-emission efficiency of the organic light-emitting element10B were investigated. The results are shown in FIG. 22.

As is apparent from FIG. 22, if the light-emitting layer 15C did notinclude C, i.e., if the width W of the light-emitting layer 15C alongthe row direction was smaller than the distance CC, the distribution ofthe film thickness of the light-emitting layer 15C in the light-emissionarea 13A of the organic light-emitting element 10R was significantlywide. This causes in-plane luminance unevenness and chromaticityunevenness. On the other hand, if the light-emitting layer 15C includedD, i.e., if the width W of the light-emitting layer 15C along the rowdirection was larger than the distance DD, the light-emission efficiencyof the adjacent organic light-emitting element 10B was significantlylow.

That is, it is proved that, if the width W of the light-emitting layer15C along the row direction is set equal to or larger than CC andsmaller than DD, the distribution of the film thickness of thelight-emitting layer 15C in the light-emission area 13A and color mixinginto the adjacent light-emission area 13A can be suppressed and thus thedisplay quality can be enhanced.

Working Examples 3-1 to 3-4

Similarly to the first embodiment, a display including the red, greenand blue organic light-emitting elements 10R, 10G, and 10B wasfabricated. In this fabrication, by adjusting the lithography conditionfor the processing of the insulating layer 14, the distance d along therow direction between an end of the light-emission area 13A and thecontact face between the insulating layer 14 and the donor substrate 40was varied to the following values: 5 μm in Working example 3-1; 4 μm inWorking example 3-2; 3 μm in Working example 3-3; and 2 μm in Workingexample 3-4.

Working Example 4

Similarly to the second embodiment, a display of three colors of red,green, and blue was fabricated. In this fabrication, the distance d wasset to 15 μm or longer.

Regarding the displays obtained as Working examples 3-1 to 3-4 andWorking example 4, the presence or absence of streak unevenness andmottled unevenness at the time of the lighting of the display %% aschecked. The results are shown in Table 1.

TABLE 1 Distance streak mottled d (μm) unevenness unevenness Workingexample 3-1 5 Absent Absent Working example 3-2 4 Absent Absent Workingexample 3-3 3 Absent Partially Present Working example 3-4 2 PresentPresent Working example 4 15 or longer Absent Absent

As is apparent from Table 1, in Working examples 3-1, 3-2, and 4, inwhich the distance d was set to 4 μm or longer, both streak unevennessand mottled unevenness were favorably suppressed compared with Workingexamples 3-3 and 3-4, in which the distance d was 3 μm and 2 μm,respectively. This might be because of the following reason.Specifically, in Working examples 3-1, and 3-2, setting the largedistance d allowed assuring of a large length of the current leakagepath and thus increased the resistance thereof, which resulted insuppression of unevenness. In Working example 4, reverse transfer itselfwas suppressed. That is, it is proved that setting the distance d to 4μm or longer can suppress adverse effects such as streak unevenness andmottled unevenness attributed to reverse transfer and thus can enhancethe display quality.

Module and Application Examples

Application examples of the displays according to the above-describedembodiments will be described below. The displays according to theabove-described embodiments can be used as a display part in electronicapparatus in any field that displays, as an image and video, a videosignal input thereto from the external or a video signal producedtherein, such as a television, digital camera, notebook personalcomputer, portable terminal apparatus typified by a cellular phone, andvideo camera.

(Module)

The displays according to the above-described embodiments areincorporated, as e.g. a module shown in FIG. 24, into various kinds ofelectronic apparatus such as Application examples 1 to 5 to be describedlater. This module is formed as follows for example. Specifically, anarea 210 exposed outside the sealing substrate 30 and the adhesive layer20 is provided along one side of the acceptor substrate 11. On thisexposed area 210, external connection terminals (not shown) are formedby extending the interconnects of the signal line drive circuit 120 andthe scan line drive circuit 130. The external connection terminals maybe provided with a flexible printed wiring board (flexible printedcircuit (FPC)) 220 for input/output of signals.

Application Example 1

FIG. 25 shows the appearance of a television to which the displayaccording to any of the above-described embodiments is applied. Thistelevision has e.g. a video display screen 300 including a front panel310 and a filter glass 320, and this video display screen 300 is formedof the display according to any of the above-described embodiments.

Application Example 2

FIGS. 26A and 26B show the appearance of a digital camera to which thedisplay according to any of the above-described embodiments is applied.This digital camera includes e.g. a light emitter 410 for flash, adisplay part 420, a menu switch 430, and a shutter button 440. Thisdisplay part 420 is formed of the display according to any of theabove-described embodiments.

Application Example 3

FIG. 27 shows the appearance of a notebook personal computer to whichthe display according to any of the above-described embodiments isapplied. This notebook personal computer includes e.g. a main body 510,a keyboard 520 for operation of inputting characters and so on, and adisplay part 530 for displaying images. This display part 530 is formedof the display according to any of the above-described embodiments.

Application Example 4

FIG. 28 shows the appearance of a video camera to which the displayaccording to any of the above-described embodiments is applied. Thisvideo camera includes e.g. a main body 610, a lens 620 that is disposedon the front side of the main body 610 and used to capture a subjectimage, a start/stop switch 630 for imaging operation, and a display,part 640. This displays part 640 is formed of the display according toany of the above-described embodiments.

Application Example 5

FIGS. 29A to 29G show the appearance of a cellular phone to which thedisplay according to any of the above-described embodiments is applied.This cellular phone is formed e.g. by connecting an upper casing 710with a lower casing 720 by a connection (hinge) 730, and includes adisplay 740, a sub-display 750, a picture light 760, and a camera 770.The display 740 and the sub-display 750 are formed of the displaysaccording to any of the above-described embodiments.

This is the end of the description of embodiments and working examplesof the present invention. However, the present invention is not limitedto the above-described embodiments and working examples but can bevariously modified. For example, in the above-described embodiments andworking examples, irradiation with laser light is carried out in thetransfer step. However, irradiation with another radiant ray such as aray from a lamp may be carried out.

In the above-described first embodiment, three times of transfer arecarried out in matching with the number of light-emmission colors.However, also in the first embodiment, a blue common layer may bedeposited by evaporation across the entire surface after only thelight-emitting layer 15C for red and green is formed by a thermaltransfer method, similarly to the second embodiment. In this case, inthe organic light-emitting element 10R, the light-emitting layer 15Ccontaining a red light-emitting material and the blue common layercontaining a blue light-emitting material are formed. However, red lightemission is dominant in the organic light-emitting element 10R becauseenergy is shifted for red, which corresponds to the lowest energy level,in the organic light-emitting element 10R. In the organic light-emittingelement 10G, the light-emitting layer 15C containing a greenlight-emitting material and the blue common layer containing the bluelight-emitting material are formed. However, green light emission isdominant in the organic light-emitting element 10G because energy isshifted for green, which corresponds to the lower energy level, in theorganic light-emitting element 10G. In the organic light-emittingelement 10B, blue light emission occurs because it includes only theblue common layer.

There is no limitation on the materials and thicknesses of therespective layers, the film deposition methods, the film depositionconditions, the conditions of the irradiation with laser light, and soon, shown for the above-described embodiments and working examples.Other materials, thicknesses, deposition methods, deposition conditions,and irradiation conditions mar, be employed. For example, the firstelectrode 13 may, be composed of IZO (indium-zinc composite oxide),instead of ITO. Alternatively, the first electrode 13 may be formed of areflective electrode. In this case, it is desirable that the firstelectrode 13 have a thickness in the range of e.g. 100 nm to 1000 nm andas high reflectivity as possible, in terms, of achievement of highlight-emission efficiency. Examples of the material of the firstelectrode 13 include elemental metals such as chromium (Cr), gold (Au),platinum (Pt), nickel (Ni), copper (Cu), tungsten (W), and silver (Ag),and alloys of any of these metals. More alternatively, the firstelectrode 13 may have e.g. a dielectric multilayer film.

In addition, in the above-described embodiments the first electrode 13,the organic layer 15, and the second electrode 16 are stacked over theacceptor substrate 1 tin that order from the substrate side, and lightis extracted through the sealing substrate 30. However, the stackingorder may be reversed. Specifically, a configuration is also availablein which the second electrode 16, the organic layer 15, and the firstelectrode 13 are stacked over the acceptor substrate 11 in that orderfrom the substrate side and light is extracted through the acceptorsubstrate 11.

Moreover, in the above-described embodiments, the first electrode 13 isused as the anode and the second electrode 16 is used as the cathode.However, the anode and the cathode may be interchanged with each other:the first electrode 13 may be used as the cathode and the secondelectrode 16 may be used as the anode. Furthermore, it is also possibleto employ a configuration in which the first electrode 13 is used as thecathode and the second electrode 16 is used as the anode, and the secondelectrode 16, the organic layer 15, and the first electrode 13 arestacked over the acceptor substrate 11 in that order from the substrateside, and light is extracted through the acceptor substrate 11.

In addition, although the specific configurations of the organiclight-emitting elements 10R, 10G, and 10B are shown for theabove-described embodiments, all of the layers do not need to beprovided but another layer may be further provided. For example, betweenthe first electrode 13 and the organic layer 15, a hole-injection thinlayer composed of chromium oxide (III) (Cr₂O₃) indium tin oxide (ITO: amixed film of oxides of indium (In) and tin (Sn)), or the like may beformed.

Furthermore, in the above-described embodiments, the second electrode 16is formed of a semi-transmissive electrode and light generated by thelight-emitting layer 15C is extracted through the second electrode 16.Alternatively, the generated light may be extracted through the firstelectrode 13. In this case, it is desirable that the second electrode 16have as high reflectivity as possible in terms of achievement of highlight-emission efficiency.

Furthermore, although the above-described embodiments are applied to anactive-matrix display, the embodiments can be applied also to apassive-matrix display. Moreover, the configuration of the pixel drivecircuit for active-matrix driving is not limited to that shown for theabove-described embodiments, but a capacitive element and a transistormay be added to the circuit according to need. In this case, accordingto the change of the pixel drive circuit, a necessary circuit may beadded in addition to the above-described signal line drive circuit 120and scan line drive circuit 130.

It should be understood that various changes and modifications to thepresently preferred embodiments described herein will be apparent tothose skilled in the art. Such changes and modifications can be madewithout departing from the spirit and scope of the present subjectmatter and without diminishing its intended advantages. It is thereforeintended that such changes and modifications be covered by the appendedclaims.

1. A display comprising an acceptor substrate including a plurality oforganic light-emitting elements, the plurality of organic light-emittingelements including a plurality of organic red light-emitting elementsarranged in a first column, a plurality of organic green light-emittingelements arranged in a second column, and a plurality of organic bluelight-emitting elements arranged in a third column, wherein each of theorganic light-emitting elements include a first electrode, an insulatinglayer having an aperture corresponding to a light-emission area of thefirst electrode, an organic layer including a light-emitting layer, anda second electrode, wherein the light-emitting layers in at least thefirst column and the second column are provided by transferring atransfer layer from a donor substrate to the acceptor substrate, andwherein when the donor substrate is arranged away from the acceptorsubstrate at a distance at least substantially equal to a height of theinsulating layer, a first A point on the donor substrate is where atangent line of the insulating layer is drawn from a left-side end of afirst light-emission area to intersect with the donor substrate, a firstC point on the insulating layer is at first A Point or vertically belowfirst A point on an upper surface of the insulating layer, and thelight-emitting layer is formed over the insulating layer to cover atleast first C point designated on the insulating layer, wherein acontact area between the insulating layer and the donor substrate in thethird column that includes the organic blue light-emitting elements islarger than contact area in the first column that includes the organicred light-emitting elements and the contact area in the second columnthat includes the organic green light-emitting elements.
 2. The displayaccording to claim 1, wherein a first B point on the donor substrate iswhere a tangent line of the insulating layer is drawn from a right-sideend of a second light-emission area positioned left-adjacent to thefirst light-emission area to intersect with the donor substrate, a firstD point on the insulating layer is at first B point or vertically belowfirst B point on the upper surface of the insulating layer, and thelight-emitting layer is formed over the insulating layer while notcovering first D point designated on the insulating layer.
 3. Thedisplay according to claim 2, wherein a second A point on the donorsubstrate is where a tangent line of the insulating layer is drawn froma right-side end of the first light-emission area to intersect with thedonor substrate, and a second C point on the insulating layer is atsecond A point or vertically below second A point on the upper surfaceof the insulating layer, wherein a second B point on the donor substrateis where a tangent line of the insulating layer is drawn from aleft-side end of a third light-emission area positioned right-adjacentto the first light-emission area to intersect with the donor substrate,a second D point on the insulating layer is at second B point orvertically below second B point on the upper surface of the insulatinglayer, and wherein a distance CC is a distance between the first C pointand the second C point, a distance DD is a distance between the first Dpoint and the second D point, and a width of the transferredlight-emitting layer along the row direction corresponding to the firstlight-emission area is greater than or equal to the distance CC and lessthan the distance DD.
 4. The display according to claim 1, wherein adistance along the row direction between an end of the firstlight-emission area and a contact face between the insulating layer andthe donor substrate is greater than or equal to 4 μm.
 5. The displayaccording to claim 1, wherein the transferred light-emitting layer isformed on an area other than a contact face between the insulating layerand the donor substrate.
 6. The display according to claim 1, wherein arib is located over the insulating layer in the third column thatincludes the organic blue light-emitting elements, and an upper surfaceof the rib contacts the donor substrate.